B12 Supplementation Improves Pregnancy Outcomes in Autoimmune Atrophic Gastritis

Vitamin B12 supplementation should be considered in women with autoimmune atrophic gastritis.

Supplementation to treat vitamin B12 deficiency improved pregnancy-related outcomes in women with autoimmune atrophic gastritis (AAG) presenting with infertility or recurrent obstetric complications, according to findings published in Digestive and Liver Disease.

AAG is characterized by the presence of parietal cell antibodies (PCA), atrophy of the gastric corpus mucosa, and often vitamin B12 deficiency. AAG frequently co-occurs with other autoimmune disorders. Vitamin B12 deficiency is associated with several specific obstetric and gynecological complications.

Researchers conducted a single-center, prospective, observational study from 2011 to 2021 at a tertiary outpatient gastroenterology clinic. The study assessed various gynecological outcomes in women diagnosed with AAG, including infertility, recurrent abortion, obstetric or fetal complications, and failure of assisted reproductive technology (ART). Researchers also examined the efficacy of vitamin B12 supplementation, so that women with AAG could pursue healthy pregnancies.

Given the life-threatening complications and severe obstetric complications, vitamin B12 should be supplemented regardless of the actual cause of its depletion.

Of the 168 women with AAG at the clinic, 14 (8.3%) presented with infertility and/or obstetric complications. Seven of the 14 reported long-lasting infertility, while miscarriage, spontaneous abortions, and unsuccessful in vitro fertilization were common obstetric complications. Fetal complications included spina bifida with myelomeningocele and embryo anencephaly.

All participants received a diagnosis of AAG due to hematological alterations, neurological alterations, autoimmune screening, and incidental endoscopic findings. Mild anemia always manifested, while serum B12 levels either were severely depleted or borderline at time of AAG diagnosis.

Following a 6-month regimen of intramuscular B12 injections dosed at 5000 UI every other week, 7 successful full-term deliveries took place, 5 patients did not wish for additional pregnancies, and 2 patients failed to get pregnant naturally. In addition to the B12 injections, the women received treatment with 5 mg of folic acid daily for 10 days after each B12 injection.    

“Our study supports the screening for vitamin B12 in all women looking for pregnancy and support an appropriate parenteral vitamin B12 supplementation starting at least six months before conception,” the study authors said. “Given the life-threatening complications and severe obstetric complications, vitamin B12 should be supplemented regardless of the actual cause of its depletion.”


Miceli E, Di Stefano M, Lenti MV, et al. Pregnancy-related complications in autoimmune atrophic gastritis: A monocentric experience. Dig Liver Dis. Published online October 23, 2022. doi:10.1016/j.dld.2022.10.003